The ‘Duets’ host offered a stripped-down version of Brit’s dance track ‘Till the World Ends,’ honoring a fan request. “We’ve had so many requests also for tonight, but for other shows as well, for me to cover the lovely Britney Spears,” she said, adding, “I know you know this song! I’m expecting everybody on these ‘Ohs’.”

Clarkson also graced fans with a special version of Houston and Carey’s ‘When You Believe,’ a duet the divas recorded in 1998 for the film ‘The Prince of Egypt.’ The ‘Stronger’ singer didn’t do it alone, though — she enlisted the help of fellow ‘Idol’ star Tamyra Gray.

Gray was one of two musical guests at the Nokia Theatre on Tuesday. Clarkson also invited Michelle Branch on the stage to perform the Wreckers’ song ‘Leave the Pieces.’ Fans certainly got their ticket’s worth at this show!

Clarkson is schedule to perform at the Pearl Concert Theater in Las Vegas on April 5, and will perform four more concerts, including the final ‘Stronger’ tour date at Beasley Coliseum in Pullman, Wash.